diff --git a/dlibrary/dlibrary.py b/dlibrary/dlibrary.py
index 787f68f..ec8ca26 100755
--- a/dlibrary/dlibrary.py
+++ b/dlibrary/dlibrary.py
@@ -873,8 +873,10 @@ def complete_prefix_number_ordering(entries):
                 if cur[level] != prev[level] and not (cur[level] == 5 and prev[level] == 0):
                     delta = cur[level] - prev[level]
                     min_delta_by_level[level] = min(min_delta_by_level.get(level, delta), delta)
-    if any(delta > 2 for delta in min_delta_by_level.values()):
-        return None
+    for level, delta in min_delta_by_level.items():
+        if delta > 2:
+            debug(f'Found a minimum delta of {delta} at level {level}, this might not be a numbering')
+            return None
 
     unified_indices.append(None)
 
@@ -919,10 +921,13 @@ def unique_hierarchical_prefix_numbering(entries, start_point=0):
                 else:
                     n = NUMBER_REGEX.match(nname(e)[pos:])
                     if n is None:
+                        debug(f'Entry {e} does not have a number after prefix')
                         return None
                     i = int(n.group())
                 numbering.setdefault((i,), []).append(e)
 
+            debug(f'Numbering found for prefix {prefix}')
+
             indices = list(numbering.keys())
             for idx in indices:
                 if len(numbering[idx]) > 1: